1. Field of the Invention
The present invention relates to a high resolution autostereoscopic display, and more particularly, to an autostereoscopic display which provides a high quality image by reducing crosstalk between a left eye image and a right eye image and time-sequentially displays a three-dimensional image with full resolution.
2. Description of the Related Art
One of the most effective methods of providing a stereoscopic image with a flat panel display is a lenticular method in which a lenticular lens array located between an display panel and a viewer to separate the viewing zones of a left image and a right image of a stereopair is used. In the lenticular method, a right eye image and a left eye image are respectively provided to a right eye and a left eye of the viewer. Conventionally, two images in a stereopair are displayed on one display panel such that one set of columns, e.g., odd-numbered columns, displays a left eye image, and another set of columns, e.g., even-numbered columns, displays a right eye image. Since the left eye image and the right eye image are displayed on one panel, the resolution of each image is half of the full resolution of the panel.
The recent development of liquid crystal display (LCD) panels with fast responding speed facilitates the display of a stereoscopic image with the full resolution of the panel by alternately displaying left and right eye images. In this case, the left eye image and the right eye image are displayed at the full resolution of the display panel. In such a system, in order to sequentially display frames, a unit selectively switching between and displaying the left eye image and the right eye image is needed.
FIG. 1 illustrates a related art autostereoscopic display disclosed in U.S. Pat. No. 5,606,455. A backlight unit (not shown) alternately operates two sets of secondary light sources that are shaped as vertical lines (that is, odd-numbered lines and even-numbered lines) disposed in a plane 12, and the refreshing of the LCD panel 11 is synchronized with the toggling between the odd-numbered lines and the even-numbered lines. The odd-numbered lines and the even-numbered lines respectively function as Lambert light sources. The LCD panel 11 is separated a predetermined distance from the light sources and provides a stereoscopic viewing zone 13.
During the odd-numbered field period, the LCD panel 11 displays alternating left and right images recorded as R and L to form an odd-numbered field image. At this time, the LCD cells modify light generated from the odd-numbered lines (the even-numbered lines are turned off) so that the right eye of the viewer receives only light transmitted through the right image columns and the left eye receives only light transmitted through the left image columns to sense a stereoscopic image.
During the even-numbered field period, columns that previously displayed right images display left images, and columns that previously displayed left images display right images. During the even-numbered field period, left and right images with half resolution are displayed using light produced by the even-numbered lines while the odd-numbered lines are turned off. The viewer views a three-dimensional even-numbered field image by viewing the light that is emitted from the even-numbered lines and modulated by left and right columns. Here, the positions of the left and right images of the LCD columns cross with their positions in the odd-numbered fields. Since human eyes have character of photogene, the odd-numbered and even-numbered half resolution fields that are sequentially shown are recognized as a full resolution stereoscopic image.
However, due to the limited response time of twisted nematic (TN) LCDs, the left and right images in the columns cannot be changed immediately, and thus the left eye can see the right image, and the right eye can see the left image. Such an undesired phenomenon is generally called “crosstalk,” and this crosstalk significantly deteriorates the quality of the stereoscopic image.
Also, since the graphics data displayed on the LCD panel is not simultaneously renewed on the entire panel but renewed line-by-line, whereas the odd-numbered lines and even-numbered lines of the light source are simultaneously turned on and off, an additional source of crosstalk arises.